Blue Chalk Sticks

Blue Chalk Sticks (Senecio mandraliscae) is the plant to reach for when you want genuine blue in the garden, not blue-ish green. The finger shaped succulent leaves hold their powdery silver blue colour all year on a low mat about 30cm tall and up to 1m across. It takes heat, drought, salt and poor soil in its stride, which makes it one of the easiest coloured groundcovers you can plant.

Why you'll love it

• Colour that never switches off. The blue is the leaf itself, not a passing flower, so the effect holds through every season.
• Real drought tolerance. Once established it needs only the occasional deep drink through a dry summer, and it prefers being forgotten to being fussed over.
• Built for the coast. Salt laden wind and sandy soil do not bother it, so it suits front line coastal beds.
• Covers ground with no fuss. No deadheading, no feeding schedule, no staking. It quietly knits into a weed suppressing mat.
• Happy in poor soil. Hungry, stony or sandy ground is fine, provided water drains away freely.

Where it works best

Groundcover and mass planting. Set plants 40cm apart for a dense blue carpet. The colour reads strongest planted in drifts against green foliage or dark mulch.

Rockeries and coastal gardens. It tucks between boulders, holds its colour in reflected heat, and shrugs off salt spray in beachside beds.

Pots and containers. A wide bowl or trough shows off the trailing stems. One caution: like other senecios the leaves are toxic if eaten, so keep it away from pets and choose something else for a dog run.

Growing Blue Chalk Sticks in Australia

Position and climate. Full sun keeps the colour intense and the growth tight; light shade turns it greener and leggier. It suits subtropical, warm temperate, Mediterranean and arid gardens, and handles light frost only, so cold district gardeners keep it in a container shifted under cover for winter. In the wet tropics the summer soil stays too damp for it.

Soil. Drainage is the only non-negotiable. In heavy ground, plant on a mound or in a raised bed with coarse sand worked through. In pots use a cactus and succulent mix.

Water and feed. Water weekly through the first warm season, then only when the soil has dried right out. A half rate controlled release fertiliser in spring is plenty.

Pruning. Trim any leggy stems in spring to keep the mat dense. The offcuts strike readily in dry mix, so one tray can eventually edge the whole bed.

What to expect when it arrives

Blue Chalk Sticks is sold in two forms: 140mm pots in packs of 10 for laying out a groundcover run, and 200mm pots in packs of 6 with fuller, established clumps. Succulents travel well, though some of the powdery blue coating can rub in transit and the odd leaf may drop. Both are cosmetic and grow out quickly.

Plants are delivered Australia wide, with delivery from $29.95. Plant into warm soil and roots take hold within weeks. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Growing blue chalk sticks: the full guide
• Browse the succulent range
• Ground covers for low maintenance gardens
• More plants for rockeries

Common questions

How far apart should I plant it for full cover?

Space plants 40cm apart. At that spacing the stems knit into a solid mat over a warm season or two, faster with an occasional deep water.

Is it safe around pets?

No. Senecio species are toxic if eaten, so it is not a plant for gardens where dogs or cats chew foliage. Plant it in beds and pots they cannot reach.

Will it survive frost?

Light frost only. A heavy frost collapses the fleshy leaves, so gardeners in cold districts do better keeping it in a pot that winters under the eaves.

Can you walk on it?

No. The leaves are brittle and snap underfoot, so it is not a lawn substitute. Set stepping stones through it instead and let the blue fill the gaps.